Update froze my xbox 360

Went to play Battlefield and was notified of an update. I ran the update and after a few hours came back and my machine was stuck on the xbox 360 screen that you get when you first turn it on (evidently it rebooted from the download and froze). I can't;
get on xbox live (seems to recognize my wireless network fine but fails to recognize xbox live), I can't to much of anything before it locks up. Any suggestions?